My son is 3 years old and will not talk

My son is 3 years old and will not talk. He can sing his abc's and count to 20 but other than that he will not speak. The doctors told us he has speech delay. At first I thought it might be autism but he looks us in the eyes and he is very loving and plays with others. He goes to school for a couple of hours a day and he has made a friend he is very found of his friend has down syndrome. Is that anything I should be worried about? I think he feels the need to take care of him. I also watch my nephew who is only 1 1/2 and he is always watching over him so i figure when he goes to school he takes care of that little boy.. Please any thoughts would help

[littlebit667]

Have you spoken with his teacher?  You can contact the school board in your area and have him evaluated by their child development team.  He might qualify for speech therapy through the school.  Otherwise, ask his doctor to make referrals for further testing.  Singing his abc's and counting to 20 just means he has memorized them, but making meaningful conversation is a different process.  Do not delay, he needs help.